National Assembly President Heng Samrin on Tuesday denied an opposition party request that parliament establish a special commission to investigate the deadly Nov. 22 bridge stampede.

A government committee determined the stampede, which killed 353 people and injured nearly 400, was an accident due to panic on the crowded Diamond Bridge.

Prime Minister Hun Sen said in days following the disaster that no officials would be held responsible for what he called a “joint mistake” in an unforeseeable event.

But opposition lawmakers said the National Assembly should establish an investigation of its own, a request Heng Samrin said was “not a necessity.”

Son Chhay, a lawmaker for the opposition Sam Rainsy Party, who signed the request with two other parliamentarians, said the denial showed “non-responsibility by the National Assembly.”

“It is regretful, but we will not give up on our investigation,” he said. “We will work closely with some non-governmental organizations to independently investigate the real cause and information on the deadly incident, and push the government to fine government officials who lacked responsibility.”

The Cambodian Center for Human Rights, an independent organziation, has said it will pursue its own investigation into the tragedy.

Speaking on “Hello VOA” Monday night, Kimsour Phirith, another lawmaker for the opposition, said the government findings were not enough.

“This was not a natural disaster like a tsunami or volcano eruption, where we were not able to know it in advance,” he said.

“Responsible officials,” he said, should be held accountable through resignations or suspensions.

However, Cheam Yiep, a National Assembly member for the ruling Cambodian People’s Party, said the government investigators had “done their job to handle the problem.”

“If we set up a committee, we don’t know what to do,” he said. “It is not our expertise.”

He suggested that the legislative body bring government representatives to answer questions, a process Kimsour Phirith said had proven ineffective in the past.

“Instead of coming to answer questions, they just come to read their answers and ignore the questions,” he said.